QUITO -- Ecuador will send its ambassador back to Colombia after recalling the envoy in December after a row over its neighbor's fumigation of drug crops along their border, the government said Wednesday.

Ecuador decided to return the ambassador after Colombia halted fumigation and created a joint commission to investigate the effects of chemical spraying on border communities, the government said in a statement.

Ecuador says Colombia's U.S.-backed spraying of herbicides to destroy coca leaf that makes cocaine hurts the environment and residents on its side. But Bogota defends the spraying as safe and key to its effort to crackdown on the drug trade.

President Rafael Correa, a left-leaning friend of Venezuela's President Hugo Chavez, is a staunch opponent of Colombia's U.S.-funded, anti-drug campaign and what his government sees as its negative fallout on Ecuador.

Ecuador's decision comes a day after a group of Ecuadorean opposition lawmakers fled to Colombia to seek protection from what they say is political persecution by Correa's government.

In December, Colombia resumed spraying along part of the 366-mile border after an 11-month pause. Washington has provided Colombia with around $4 billion in mostly military aid since 2000 to fight armed groups and drug trafficking.